1. Field of the Invention
The present invention relates to a high-frequency relay suitable for switching a high-frequency signal.
2. Description of the Related Art
In the related art, there is disclosed a high-frequency relay in Japanese Patent Laid-Open No. 2001-345036. In this high-frequency relay, an electromagnetic block is excited and demagnetized to rotate a movable iron piece. A movable block is pushed down by a push-in spring interlocking with a rotation of the movable iron piece so as to close a contact. The movable block is pushed up by a return spring so as to open the contact. The movable block has a movable contact piece, and a support portion formed in the central portion of the movable contact piece. The support portion moves up and down through an opening portion formed in a ground plate so as to connect/disconnect the opposite end portions of the movable contact piece with/from fixed contacts under the ground plate. Thus, a transmission line is switched on/off.
However, in the related-art high-frequency relay, the return spring made from a metal material is provided integrally with the upper portion of the ground plate because the return spring affects the high-frequency characteristic about the isolation of the transmission line. Accordingly, a useless space is formed under the ground plate so that the height of the high-frequency relay increases. In addition, there is a problem that the structure of the high-frequency relay becomes complicated and the workability thereof deteriorates so that the cost increases.
It is therefore an object of the present invention to provide a high-frequency relay which is small in size, simple in structure and easy to work and which can be manufactured at a low price.
As means for solving the foregoing problem, the invention provides a high-frequency relay comprising:
a base block having fixed terminals insert-molded to expose fixed contacts;
an electromagnetic block having a coil wound around an iron core through a spool, and mounted on the base block; and
a movable block having movable contacts driven in accordance with excitation and demagnetization of the electromagnetic block so as to be connected with and disconnected from the fixed contacts of the base block, the movable block having a movable iron piece whose opposite end portions are to be connected with and disconnected from the fixed contacts of the fixed terminals respectively; and
a return spring for elastically supporting the movable block, the return spring being disposed to be biased to one of the fixed terminals on the base block.
With this configuration, an enough distance between the return spring and one of the fixed terminals can be secured so that desired insulation performance can be secured. In addition, the return spring can be disposed in a surplus space on the upper surface of the base block so that the height of the high-frequency relay can be suppressed.
In order to enhance the insulation performance, it is preferable that: each of the fixed terminals includes a fixed contact portion in which the fixed contact is formed, and a foot portion provided to extend from the fixed contact portion, and the base block includes a recess portion enclosed by a protruding strip portion formed in an upper surface of the base block, and a seat portion being provided in the recess portion so that the fixed contact portion can be disposed on the seat portion while a surface and side edges of the fixed contact portion are exposed.
It is preferable that the high-frequency relay further comprises a movable iron piece which rotates due to excitation and demagnetization of the electromagnetic block, the movable iron piece having s push-in spring for pushing the movable block in accordance with a rotation of the movable iron piece, wherein the movable block is connected with and disconnected from the base block due to the push-in spring, so that force acting on the movable block from the push-in spring and force acting on the movable block from the return spring cancel each other as to components other than components in a direction in which the movable block is connected with and disconnected from the base block. In this case, the moving direction of each movable block can be stabilized.
It is preferable that the return spring includes a rectangular frame portion and an elastic tongue piece extending from an inner edge of the rectangular frame portion, and the movable block is supported by a forward end portion of the elastic tongue piece so that the elastic tongue piece and the rectangular frame portion can be deformed elastically. In this case, the elastic force per displacement can be set to be weak.
It is preferable that a displacement prevention function is formed in at least one of the return spring and the movable block.
In this case, the movement of each movable block can be stabilized.
It is preferable that the return spring includes a lock portion in the rectangular frame portion, and the base block includes a lock guard portion in which the lock portion is locked. In this case, the displacement of the return spring when the return spring is elastically deformed can be prevented surely in spite of a simple structure.